The present invention relates to a semiautomatic transmission for vehicles, construction machines and similar, which semiautomatic transmission comprises a synchro-mesh transmission, which has an electrically controlled gear shift mechanism, a sensor for measuring the engine torque, and sensors for measuring the rotating speeds of drive line shafts located immediately before the transmission or after the transmission, which sensors transmit signals corresponding to measured quantities to the electric control unit for selecting a gear suiting the actual driving situation.
Semiautomatic transmissions are known in the prior art, and they are widely used in the drive line systems of motor vehicles and similar equipment. Conventional semiautomatic transmissions are arranged in such a way that the clutch and the transmission are specially designed in order to make the clutch pedal or similar unnecessary. On the other hand, these systems have a normal gear shift selector for selecting the desired driving gear. In these systems the clutch and the transmission must be specially designed, and the clutch is usually a kind of centrifugal clutch by which the engagement of the drive line depends on the engine speed of revolutions. Usually there is also a torque converter between the clutch and the transmission for evening up the jerks due to the engagement of the gear thus protecting the transmission. From the point of view of the driver, a conventional system such as this, when installed for instance in a vehicle, differs from a usual manual transmission only in that the clutch pedal has been omitted or that it is not necessary to use the clutch pedal when shifting the gear. Therefore it is the driver of the vehicle who always selects the desired driving gear. Thus the driver must concentrate on the selection of the gear and distract his attention from the actual driving.